Not sure if this is the right area to post this so please let me know if there's another place that's more appropriate. I have a Hybrid system (specs are in my sig). I'm working through some of my issues since downloading LinuxMCE and going through the install process. I am currently using 0710 beta2 since I had quite a few problems getting the audio and video to sync up during DVD playback on 0704.

My current issue is getting playback on DVD's to smooth out. They are very choppy. After doing some research, I see that DMA is getting disabled after I put a DVD in the system. Below are the related messages from /var/log/messages.

--Notice that the using_dma parameter is set to off. I turn it on and tell it to keep the settings after reboot with the following command. linuxmce@dcerouter:~$ sudo hdparm -d1 -k1 /dev/hdc/dev/hdc: setting using_dma to 1 (on) setting keep_settings to 1 (on) using_dma = 1 (on) keepsettings = 1 (on)

--After running this command and rebooting, the settings are kept until I put in a DVD and then the drive is switched to using_dma = off again. I have verified IDE cable is connected properly and have even switched out with another one to rule that out.

I have had some problems with my box, using other different distributions, same as you have explained here...

A) not sure if hdparam values are carried forward between reboots.

B) whats the kernel parameters you are using. Easiest to find it by using "cat /proc/cmdline".

If you have ide=nodma, then that will disable dma for all the ide bus. I am not sure, but that supersedes any another config you may want to do..

If ide=nodma does not exists in your /proc/cmdline then it means your motherboard/ide bus does not support dma. In that case, try rebooting your box with ide=nodma to see if that helps.. I have had better luck with ide=nodma specifically set when kernel boots up.

A) It does seem that the hdparm values are carried between reboots because the dma is on when I first start up the machine without a DVD in the drive. However, dma turns off after putting the DVD in and the error messages in the OP are displayed in /var/log/messages. Running hdparm -i /dev/hdc after putting the DVD in the drive shows that it is turned off after loading the DVD.

I tried adding the ide=nodma using vi but it will not allow me to save the file. I read something about the file cannot be modified directly using vi but can't quite figure out the syntax to get the info in the file and not loose the line that's already in there. Here's what I tried:linuxmce@dcerouter:~$ gksudo echo 'ide=nodma' >/proc/cmdline-bash: /proc/cmdline: Permission denied

A) It does seem that the hdparm values are carried between reboots because the dma is on when I first start up the machine without a DVD in the drive. However, dma turns off after putting the DVD in and the error messages in the OP are displayed in /var/log/messages. Running hdparm -i /dev/hdc after putting the DVD in the drive shows that it is turned off after loading the DVD.

I tried adding the ide=nodma using vi but it will not allow me to save the file. I read something about the file cannot be modified directly using vi but can't quite figure out the syntax to get the info in the file and not loose the line that's already in there. Here's what I tried:linuxmce@dcerouter:~$ gksudo echo 'ide=nodma' >/proc/cmdline-bash: /proc/cmdline: Permission denied

Bear with me as I am not too fluent in Linux...

Hmmm... the problem with that line is that you need to enter it as below;

Well apart from the fact that /proc/cmdline is read-only it probably wouldn't do much good as those parameters were used by the kernel at boot time.

If you want to change them you can edit /boot/grub/menu.lst instead and reboot. Extra options kan be added to the "kernel" lines. You can also do this from GRUB itself (press escape when it tells you to during the boot) but then the settings aren't saved, which is handy when experimenting with boot parameters.

Thanks for the suggestions.I went ahead and updated the /boot/grub/menu.lst file to add the ide=nodma. Here's the area of that file that I modified.title Ubuntu 7.10, kernel 2.6.22-14-genericroot (hd0,0)kernel /boot/vmlinuz-2.6.22-14-generic root=/dev/sda1 ro quiet splash ide=nodmainitrd /boot/initrd.img-2.6.22-14-genericquiet

I rebooted after making the change and it seemed to make no difference. Video playback is still very choppy.

I decided that maybe it was the DVD drive so I swapped it out for another one. (Lite-On SHW-1635S) and I'm having the same issues. On bootup, the hdparm /dev/hdc still shows; using_dma = 0 (on)However, after putting a DVD in the drive, it switches the output of the hdparm /dev/hdc command to: using_dma = 0 (off)It's still showing the same messages in the /var/log/messages file about disabling DMA. (see OP)

What's odd is that this is the same mobo used in the video if I'm not mistaken, I've had issues playing DVD's on both 0704 and 0710 now. Am I the only one experiencing this issue?

Thanks for the suggestions.I went ahead and updated the /boot/grub/menu.lst file to add the ide=nodma. Here's the area of that file that I modified.title Ubuntu 7.10, kernel 2.6.22-14-genericroot (hd0,0)kernel /boot/vmlinuz-2.6.22-14-generic root=/dev/sda1 ro quiet splash ide=nodmainitrd /boot/initrd.img-2.6.22-14-genericquiet

I rebooted after making the change and it seemed to make no difference. Video playback is still very choppy.

I decided that maybe it was the DVD drive so I swapped it out for another one. (Lite-On SHW-1635S) and I'm having the same issues. On bootup, the hdparm /dev/hdc still shows; using_dma = 0 (on)However, after putting a DVD in the drive, it switches the output of the hdparm /dev/hdc command to: using_dma = 0 (off)It's still showing the same messages in the /var/log/messages file about disabling DMA. (see OP)

What's odd is that this is the same mobo used in the video if I'm not mistaken, I've had issues playing DVD's on both 0704 and 0710 now. Am I the only one experiencing this issue?

I'm not even sure if DMA is the issue. Are there any other avenues that I might want to look into to improve the DVD playback experience?

Thanks again everyone!

Hi again...

Zaerc's right /boot/grub/menu.lst is what you should be editing/updating to manage what Grub does at boot.

Sorry... i did not really read the thread properly and was too focussed on helping your edit /proc/cmdline !!

Now... as to your DMA problem... I would suggest getting yourself (or borrowing) another Optical drive and hooking that up to test whenther the choppiness and DMA problem goes away... I bet it will. My thinking is that it might well be your drive... we've seen this in the past at least.

Thanks for the suggestion.In my last post I mentioned swapping out the DVD drive and still having the same issues. I'm wondering if I need to install 0704 again to see if DMA is turned off on that one as well. Possibly it's just something to do with this 0710 beta 2 build? I would think others would notice and would have complained of these choppy playback issues as well if it was a 0710 beta 2 issue.

I'm also wondering if I might be better off going with a SATA DVD drive? It seems that there are quite a few using LinuxMCE with success. I'm going with the quote from "The Edge" on this one. "What one man can do, another can do!" http://www.youtube.com/watch?v=KZS14_yec3AI just need to find the key to fixing this problem.

Thanks for the suggestion.In my last post I mentioned swapping out the DVD drive and still having the same issues. I'm wondering if I need to install 0704 again to see if DMA is turned off on that one as well. Possibly it's just something to do with this 0710 beta 2 build? I would think others would notice and would have complained of these choppy playback issues as well if it was a 0710 beta 2 issue.

I'm also wondering if I might be better off going with a SATA DVD drive? It seems that there are quite a few using LinuxMCE with success. I'm going with the quote from "The Edge" on this one. "What one man can do, another can do!" http://www.youtube.com/watch?v=KZS14_yec3AI just need to find the key to fixing this problem.

Hmmm... I wonder if your current optical drive is suffering choppy playback because its sharing an IDE channel with another of your drives. Thats possible.

I don't think that its a problem per se with 0710 as we have not seen this problem at all on any of test Cores.

No dice there either. My system is currently setup with the 250 gig drive on a sata connection. The only thing on the IDE cable is the DVD drive. Any other suggestions?

did you also swap the cable but only the drive? The error not returning "SeekComplete" strongly suggests you have bad drive hardware/medium or a problem with the ide driver. The last one is very uncommon.

I had just swapped out the drive and not the cable. I made the assumption that the new cable that came with my mobo couldn't be bad. WRONG!Swapping out the cable solved the issues being logged to /var/log/messages and also seems to have cleaned up the DVD playback.

I had just swapped out the drive and not the cable. I made the assumption that the new cable that came with my mobo couldn't be bad. WRONG!Swapping out the cable solved the issues being logged to /var/log/messages and also seems to have cleaned up the DVD playback.